Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D309/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings
  • C07D309/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings having no double bonds between ring members or between ring members and non-ring members
  • C07D309/04—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
  • C07D309/06—Radicals substituted by oxygen atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D309/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings
  • C07D309/16—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member
  • C07D309/28—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only ring hetero atom, not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D309/30—Oxygen atoms, e.g. delta-lactones

Definitions

• the present invention relates to a process for lactonizing mevinic acid or analog thereof. More particularly, the present invention relates to a process for preparing lovastatin and simvastatin in a high yield which comprises (1) performing a lactonization of mevinic acid and analog thereof compounds in the presence of a dehydrating agent without an acid catalyst under nitrogen sweep; and then (2) making crystals at a high temperature.
• Hypercholesterolemia is known as to be one of the prime risk factors for ischemic cardiovascular disease, such as arteriosclerosis. Bile acid sequestrants have been used to treat these diseases. They seem to be moderately effective but they must be consumed in large quantities, i.e. several grams at a time and they are not very palatable.
• statins are reported to exist in a dihydroxylic acid form with an open circular structure as depicted in Formula 2 and in a lactone form as depicted in Formula 1.
• Z is hydrogen, ammonium or metal cation
• R is a radical of Formula 3 and R 1 is H or CH 3 .
• Statins are known to be active in a dihydroxylic acid form physiologically, but usually administered in a lactone form for patients. Therefore, it is necessary to develop an efficient method to perform a lactonization in a high yield. Since the lactonization is an equilibriated process, specific means should be utilized to transfer the equilibrium toward lactones as shown in Reaction Formula 1 in order to produce lactonized products in a high yield.
• hydroxylic acid substrate works as an acid catalyst and thus reduces a reaction velocity, depending upon the substrate consumed so as to take a longer time period for the reaction and to increase by-products generated.
• 3-hydroxylactone a product is reacted with free acids during the extended period.
• heterodimers produced through the esterification between 3-hydroxy group of 3-hydroxylactone and the free acids is increased in the amount as depicted in Formula 1 a .
• R and R 1 are defined as described above.
• Korean patent publication No. 97-11286 discloses another process for preparing lactones. It involves treating the free hydroxylic acid or ammonium or metal salt derivatives of mevinic acid or analog thereof in a water miscible organic solvent (especially acetic acid medium) which exhibits a sufficient solubility difference between the hydroxylic acid and lactone, and a strong acid catalyst. After the free hydroxylic acid-lactone equilibrium is established, water is added in an amount sufficient to effect complete crystallization of the lactone from the reaction medium.
• a water miscible organic solvent especially acetic acid medium
• U.S. Pat. No. 5,917,058 has illustrated the process for the preparing lactones, in which dihydroxy groups of statins or analog thereof, especially in an ammonium salt, are reacted with acetic acid medium without adding an acidic catalyst and without removing water or ammonia at 35 ⁇ 40° C., and then insoluble solvent such as water, hexane, cyclohexane and the like is added to make lactones.
• insoluble solvent such as water, hexane, cyclohexane and the like is added to make lactones.
• acetic acid as a solvent is utilized in 3 ⁇ 7-fold larger amount than that of the reactant and should be neutralized with bases, which the neutral salt (ammonium acetate) is produced and remained in the final lactone compounds.
• the object of the present invention is to provide a process for preparing lactone compounds, which is convenient and economical as well as decreases the content of heterodimers remarkably.
• the present invention relates to a process for lactonizing mevinic acid or analog thereof. More particularly, the present invention relates to a process for preparing a compound of Formula 1 which comprises (1) step of performing a lactonization of Formula 2 in the presence of a dehydrating agent and without an acid catalyst under nitrogen sweep; and then (2) step of making lactone product in crystals.
• Z is hydrogen, ammonium or metal cation
• R is a radical as depicted in Formula 3 and R 1 is H or CH 3 .
• the dehydrating agent can be one selected among a group comprising magnesium sulfate, sodium sulfate, calcium chloride, molecular sieve and like.
• magnesium sulfate can be used.
• the dehydrating agent completes the reaction by removing water generated in the equilibriated reaction. As a result, it reduces contaminants of by-products with shortening the period of the reaction time. Therefore, it affects outstandingly to enhance the yield of lactone compounds.
• the time period for the reaction can be reduced to 2 ⁇ 4 hours and preferably to about 3 hours.
• the amount of the dehydrating agent can be in the range of 1 ⁇ 2 equivalent against 1 M dihydroxy of statin or analog thereof, especially in an ammonium salt form and more preferably in the range of 1.2 ⁇ 1.5 equivalent.
• the solvent utilized in the lactonization can be adopted among toluene, ethylacetate, isopropylaceate, acetonitrile, acetone, dichloroethane, chloroform and the like as a neutral organic solvent and preferably selected among toluene, acetonitrile, acetone or dichloroethane.
• the organic solvent used in the present invention described above consists only one solvent and thus can be used by retrieving the solvent by simply distilling, which contributes to reduce the cost a lot.
• the lactonization in the present invention is accomplished under nitrogen sweep at a reflux temperature.
• the reaction time is adjusted not to exceed 4 hours preferably, since by-products formed increase after more than 4 hours and more preferably, the reaction proceeds for about 3 hours.
• the solvent adopted for the crystallization can be one selected among water, ethanol, isopropyl alcohol, n-hexane, cyclohexane, toluene, ethylacetate, isopropylacetate, acetonitrile, acetone, dichloroethane or chloroform or a mixed solvent comprising more than one of these.
• the mixed solvent can be made by blending between ethanol and water or between toluene and cyclohexane.
• the solvent for the crystallization can be a mixed solvent comprising 8 ⁇ 10 volume portion of water and 8 ⁇ 10 volume portion of ethanol, or a mixed solvent comprising 2 ⁇ 3 volume portion of toluene and 19 ⁇ 21 volume portion of cyclohexane against 1 weight portion of a dihydroxy, especially an ammonium salt of statin and analog thereof.
• the solvent amounts of water/ethanol and toluene/cyclohexane are more than this scope, the contaminants might not be removed easily as well as the crystallization of the solid might be lowered, which seems not preferable.
• the process for crystallization is performed preferably at the temperature range of 30 ⁇ 40° C. by using the mixed solvent of water/ethanol and tolene/cyclohexane.
• the temperature for the crystallization is less than 30° C., it is difficult to remove contaminants and in case that it is more than 40° C., it is not preferable since the crystallization of the solid might be lowered. Consequently, the stability is reduced disadvantageously.
• lovastatin and simvastatin in a highly purified state can be produced in a high yield and especially, the whole procedure is convenient and economical as well as the amount of heterodimers, by-products can be reduced remarkably.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Pyrane Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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Citations (4)

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• 2001
  • 2001-08-27 KR KR10-2001-0051796A patent/KR100407758B1/ko not_active IP Right Cessation
• 2002
  • 2002-07-06 WO PCT/KR2002/001281 patent/WO2003018570A1/en active Search and Examination
  • 2002-07-10 DE DE60226203T patent/DE60226203T2/de not_active Expired - Lifetime
  • 2002-07-10 AT AT02015509T patent/ATE393151T1/de not_active IP Right Cessation
  • 2002-07-10 EP EP02015509A patent/EP1288212B1/de not_active Expired - Lifetime
  • 2002-07-23 US US10/200,174 patent/US6649775B2/en not_active Expired - Fee Related
  • 2002-07-29 CN CNB021270864A patent/CN1193022C/zh not_active Expired - Fee Related
  • 2002-08-26 JP JP2002245931A patent/JP2003096071A/ja active Pending

Patent Citations (4)

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